First I have the stock barrel that came with the G29. Because I fire hot ammo and had the slide milled and fitted with an RMR red dot I discovered that hot 10mm ammo overpowers the little stock barrel. The bullets were all over the place and I cold not zero the RMR. Next I bought KKM match barrel. That worked and I got enough spin (or what ever is going on) to get very tight groups and I was able to zero the RMR. I figured more is better so I bought a Lone Wolf 6 inch match barrel. This works very well the bullets develop full rated velocity. The groups are even a little tighter. It's almost becomes a G40, but not as heavy. This would be my choice for hunting but NOT CC because the long barrel is difficult to CC. I also bought a 10mm to .40 caliber conversion barrel. This works remarkably well! 40 caliber is a lot less expensive than 10mm and the recoil feels almost the same to me. This is an economical way to practice. I also bought a ported barrel that extends slightly beyond slide and has two ports/vents on the top of the barrel. I thought this might reduce flip, but I can't say I notice a difference. I have two problems with this barrel. 1) Those two slots provide a place for the lanyard on my trigger holster (like a MIC) to get hung up on. 2) I have experienced FTF with this barrel! It's happened too many times when I using this ported barrel. Re-zeroing the weapon every time I switch barrels burns through ammo and is a waste of time. I decided to take a photo of the setting needed on my RMR for each of my barrels. This also works very well, saving time and money. I have attached a few examples of the photos of settings I use for zeroing various barrels.